Abstract:

The sensitivity index of the river valley runoff process as dependent variable versus the atmospheric circulation factors as independent variable was defined based on the theory of sensitivity analysis. The coupling mechanism of the atmospheric circulation factors to the runoff process was identified by the BP algorithm to get the mapping relationship between the dependent and independent variables. Based on the historical data of the Nenjiang river valley since the 1950s, the sensitivity index of the valley runoff to the atmospheric circulation index was calculated. It was found that the key factors of atmospheric curculation affecting the Nenjiang river valley runoff process are the area and intensity of circumpolar cyclone, circumfluence at middle latitudes, and Tibetan plateau circumfluence.

Key words: hydrology, runoff, atmospheric circulation, sensitivity analysis, mid-andlong, term runoff forecasting